This invention relates to a disc in a disc-brake for vehicle use, more particularly to the provision of a disc highly effective in preventing noise in the disc-brake.
Disc-brakes are generally liable to produce an unpleasant noise or squeal when the brake pedal is depressed, for which noise various preventive attempts have been taken. It is well known that the squeal of the disc-brake may be caused by the resonance of a brake-pad (hereinafter simply called pad), whereby restriction of pad movement or damping of the same is effective preventing squealing.
The conventional techniques therefor, as, for example, in Toku-Kai-Sho-51-38868, Toku-Kai-Sho-51-39311 laid open in Japan, etc., possess disadvantages, such as increased component parts, complicated parts configuration, or difficulty of assembly. Morover, where restriction of pad movement is attempted, a further problem, a drag phenomenon, arises often, due to a residual sliding contact of the pad on the disc even after the release of the brake pedal.
The inventor of this invention succeeded some time ago in preventing the squeal due to the resonance of a pad, by restricting the movement of the pad through an improvement in the disc itself, not in the pad or other members carrying the same. That improvement, an invention itself, is now pending as with patent application with No. Toku-Gan-Sho-51-134877 filed with the Japanese Government Patent Office.
Since the disc rotates together with the wheel and the pad is stationary, being mounted on a non-rotating place through a caliper, a mounting bracket, etc., it would seem impossible to restrict the movement of the stationary pad by means of the rotating disc. This assumption of impossibility has been discovered to be incorrect.
The present invention is aimed at a further improvement of the aforementioned invention. While the previous invention is based on the concept of restricting pad movement through its engagement between a few great grooves and/or ribs, disposed on the surface of the disc around its rotation axis, and mating ribs and/or grooves naturally formed on the surface of the pad corresponding to those on the surface of the disc, the present invention aims at a drastically altered form of the grooves and/or ribs for attaining an effect like that of the previous invention. That is to say, a number of circular ground scores or cut scores are formed on the surface of the disc around its rotation axis. It will be quite naturally understood that ground scores or cut scores having a surface coarseness or roughness above a certain level are highly effective in restricting movements of the pad in the direction parallel to that of the disc surface, by imagining the feeling of cleaning the surface of a phonograph record with a wiper.